Engine hoods need to be quite strong since they are generally handled without taking precautions. That is why they are often made out of sheet metal, even though some hoods have recently appeared on the market that are made out of high strength thermoplastics.
This strength presents at least two drawbacks.
Firstly, in the event of a pedestrian coming into collision with the front of the vehicle, the strong hood runs the risk of striking the pedestrian directly.
Secondly, even in an impact at low speed, commonly referred to as “insurance knocks”, this type of strong hood is easily damaged. It then needs to be replaced, and even for impacts that are not serious, this requires the vehicle to be out of operation for quite a long time and involves substantial repair costs.
This problem becomes particularly severe when the hood is a plunging hood covering not only the top of the engine compartment, but also extending down over the front of the vehicle to the bumper shield, as is commonly the case for sports cars.
Furthermore, under such circumstances, the join between the hood and the shield does not touch accurately, since vertical clearance must be left between these two parts in order to enable the hood to be slammed shut.
To make this clearance acceptable in appearance, use is made of the trick whereby the adjacent edges of the hood and the shield are offset so that they do not lie one above the other, even though they remain in the same horizontal plane.
As a result, the join between the hood and the shield appears to be touching when the vehicle is seen from in front. However, when seen from the side the offset is clearly visible, but that is considered to be less unpleasing in appearance.